Accession Number : ADA474490


Title :   Impact of L/D on 90 Degree Sharp-Edge Orifice Flow with Manifold Passage Cross Flow (Preprint)


Descriptive Note : Journal article


Corporate Author : SCIENCE AND TECH APPLICATIONS LLC MOORPARK CA


Personal Author(s) : Nurick, W H ; Ohanian, T ; Talley, D G ; Strakey, P A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a474490.pdf


Report Date : 30 Apr 2007


Pagination or Media Count : 35


Abstract : A process model is proposed to explain the various stages of flow conditions that are observed by measurement as the flow transitions from non-cavitation to cavitation (turbulent flow), supercavitation, and finally separation in sharp-edge 90 degree orifices. This study includes orifice L/D from 1 to 10, orifice diameters of nominally 0.048 and 0.078 inch, and upstream pressures from 100 to 1500 psi as well as manifold cross flow velocity of from 6 to 60 ft/sec. The results support two different first order models, one for cavitation and the other non-cavitation in turbulent flow. Under full cavitation conditions the discharge coefficient is related to the contraction coefficient and the cavitation number to the 1/2 power. In the non-cavitation full flow regime the head loss is related to the loss coefficient and the dynamic pressure at the orifice exit. Both the head loss and contraction coefficient were found to be a strong function of the ratio of upstream velocity-to-orifice exit velocity. The area ratio between the manifold and the orifice were also found to have a significantly influence the contraction coefficient. Relationships are proposed to explain the processes leading to hydraulic flip (separation) and prediction of occurrences that include inception of cavitation, supercavitation, and separation.


Descriptors :   *ROCKET ENGINES , *ORIFICES , LABORATORY TESTS , EXPERIMENTAL DESIGN , ANALYSIS OF VARIANCE , TURBULENT FLOW , CAVITATION , COLD FLOW , COMPUTATIONAL FLUID DYNAMICS , FLOW RATE , MANIFOLDS(ENGINES) , INJECTORS , FLOW SEPARATION


Subject Categories : Fluid Mechanics
      Rocket Engines
      Test Facilities, Equipment and Methods


Distribution Statement : APPROVED FOR PUBLIC RELEASE